Dell Optiplex 755 Desktop PC?

New to CNC. Would an old Dell Optiplex 755 Desktop PC be a good starter machine??

Hi

You need to specify exactly what the machine is.

Dell make several levels of computer under the same model number and then change the spec during production, whilst retaining the same number.

Some are good and some complete dogs

You will see from the latency page
wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test
that the Dell 745, one model down from yours, return awful figures and others are pretty good, but yours does not feature.

regards